Flow regulator for piston-equipped cylinder



FLOW REGULATOR FOR PISTONEQUIPPED CYLINDER Filed Sept. 15, 1958 A. B. NEWTON Feb. 5, 1963 2 Sheets-Sheet 1 Nl/ENTOR:

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United States Patent 3,076,593 FLOW REGULATOR FOR PISTON-EQUIPPED CYLINDER Alwin B. Newton, Wichita, Kans. (136 Shelbourne Drive, York, Pa.) Filed Sept. 15, 1958, Ser. No. 760,955 Claims. (Cl. 230-19) This invention relates to a flow regulator for a pistonequipped cylinder, and, more particularly, to a flow regulator for the fluid intake line for such a cylinder.

This invention finds utility in the field of refrigeration compressors, but has application also to other operations in which a fluid is pressurized in a piston-equipped cylinder.

In certain applications of air conditioning, the compressor is operated irrespective of whether refrigeration is calledfor. One prime example is in automotive re frigeration. There, the compressor piston is directly coupled to the crankshaft and reciprocates whether refrigeration is needed or not. This operation is currently justified, since automobiles are overpowered and the power utilized in the refrigeration compressor does not seriously aifect the engine performance. It would be desirable, however, to provide means which would regulate the amount of compression effected by the compressor as a function of the refrigeration load. It would further be desirable to provide means to reduce the capacity of the compressor during periods when little or no compression is required. These, then, form some of the objectives of this invention.

Another objective is to provide a novel flow regulator for a piston-equipped cylinder. Still another object is to provide means in the fluid intake to a piston-equipped cylinder that regulates the flow of fluid thereto. Yet another object is to provide means cooperating with the piston of a piston-equipped cylinder that regulates the degree of capacity or unloading of the cylinder and thereby correlates the compression developed by the cylinder to the load requirements.

A further object of the invention is to provide a novel structure of the character indicated in which a flow fitting or port member is sealingly and positionably mounted in a fluid intake to a piston-equipped cylinder with the piston being movable into engagement with the fitting or port to close the same. A still further object is to provide in the apparatu described in the object immediately preceding, means for positioning the fitting or port member which is responsive to a thermal signal. A yet further object is to provide, in the apparatus just described, time delay means which postpones the imposition of all or part of the load on the compressor until it has started up. Other objects and advantages of this invention can be seen as this specification proceeds.

This invention will be described in conjunction with the accompanying drawing, in which-- FIG. 1 is an elevational view, partly in section and partly diagrammatic, of apparatus embodying the teachings of this invention; FIG. 2 is a cross-sectional view, taken along the line 22 of FIG. 1; FIG. 3 is a view similar to FIG. 1 but showing a modified form of the invention; FIG. 4 is. a cross-sectional view taken along the line 44 of FIG, 3; and FIG. 5 is a view similar to FIG. 3 but showing a plurality of cylinders in a compressor.

In the illustration of the invention given in FIG. 1, the numeral designates generally a cylinder which has a piston 11 slidably mounted therein and which is reciprocated by a piston rod 12 coupled to piston 11 through a wristpin 13 in a conventional fashion.

Cylinder 10 is equipped with an outlet port 14 communicating with an outlet manifold -15, the manifold 3,076,593 Patented Feb. 5, 1963 supporting an exhaust check valve 16. The foregoing arrangement is well known, so that the details given are shown in the particular form they are merely for the sake of completeness of illustration. For example, valve 16 is equipped with a spring 17 mounted about a post 18, so that upon the development of a predetermined pres sure within cylinder 10, the valve 16 will open until it abuts post 18 to permit outflow of the compressed fluid through manifold 15.

Fluid is delivered to cylinder 10 through an intake conduit designated generally by the numeral 19 and which is equipped with a slidable flow fitting generally designated 20. Flow fitting 20, which may be generally tubular in nature, provides a flow passage 21 therein, the fitting 20 being in sealing engagement with the interior walls of conduit 19. The inner end of fitting 20 is equipped with a constricted port or orifice 22 provided by an inwardly-extending flange 23. Shown in sealing engagement therewith and slidably mounted therein is a' piston extension 24.

Mounted within conduit 19 and bearing against one end of fitting 20 is a coiled spring 200 which is operative to urge fitting 20 against stop 20b and into the position, shown in FIG. 1. The spring 20a supplies a downward force against fitting 20 urging it into engagement with stop 2%, the downward force exerted being slightly in excess of the maximum desired difference in pressure between suction and discharge multiplied by the projected area of the annulus formed by the opening at 23 and the outer diameter at 20. This then provides an internal load limitation on the device.

The intake conduit is equipped with a solenoid 25 which is energized through an electrical connection 26. Interposed in the electrical circuit delivering current to solenoid 25 is a manual or safety switch 27, a thermostatic switch 28, and a time delay switch 29, the functions of which, as well as the operation of the apparatus just described, can be appreciated from the following description:

Operation It is believed that the operation of the apparatus just described can be readily appreciated when the apparatus is considered as a part of an automobile refrigeration system. In such a case, the manifold would be communicated with a condenser, expansion valve, and evaporator. The evaporator in turn would be communicated with the suction intake conduit 19. The piston 11 could be energized from the engine crankshaft through the piston rod 12. The manual or safety switch could be providedas part of the ignition switch, while the thermostat 28 would be responsive to the temperature within the passenger space of the automobile.

When the car is started, switch 27 is closed, along with the time delay switch 29. If the thermostatic switch 28 is in the position shown, this will energize solenoid 25 to raise fitting 20 to a position above extension 24 during the entire piston cycle.

Thus, no compression is provided and the refrigerant merely is drawn into and forced out of cylinder 10 through the intake opening 22. The cylinder 10 now acts as a compressor in a completely unloaded condition (i.e., with its capacity to pump reduced to zero). A short time after the start-up time delay switch 29 will open, breaking the supply of electrical current to solenoid 25, and spring 20a will force fitting 20 to the position shown. The compressor then will be loaded, and once each cycle extension 24- moves downwardly a sufficient distance to become disengaged from fitting 20 and permit the inflow of refrigerant fluid. Shortly thereafter, the upward stroke of piston 11 again causes extension 24 to engage the fitting 20 and seal it against further flow of fluid therethrough, permitting the cylinder to develop compression on the refrigerant fiuid which is finally discharged through valve 16. Under the operation just discussed, the thermostatic switch 28 is in the position in which refrigeration is called for. Should the switch be in the alternative position, corresponding to no demand for refrigeration, the solenoid 25 will be continuously energized and the cylinder will remain in an unloaded condition.

For automotive application, it is possible to combine the functions of switches 27 and 29 into a single switch which is closed during the cranking cycle and which therefore may be the same switch which energizes the starting solenoid of the engine. In such an event, the combined switch could be disposed in parallel to switch 28.

For the sake of clearness of illustration, only one cylinder has been shown, but it is to be appreciated that the invention can be satisfactorily employed in apparatus where a plurality of cylinders are present.

It is also to be appreciated that by varying the strength of spring a, a small degree of loading can be achieved even when solenoid is energized. This may be desirable in some cases even though refrigeration is not called for in the evaporator, since the slight refrigeration developed under very small loading could be dissipated in merely cooling the engine block or, more specifically, the cylinder 10 in which piston 11 is continuously reciprocated. However, excellent results can be obtained for automotive purposes when the fitting 20 has a limited range of movement in which at the extreme upper limit it is spaced from extension 24 during the entire cycle of operation of piston 11, while at the lower limit of its range of movement it is engaged by extension 24 for a major portion of the cycle.

Full capacity reduction is possible in automotive work because the compressor heat is dissipated by the flow of air (even though relatively warm) over the compressor. This may not always be the case in motor-driven stationary units.

Ordinarily, no additional suction line is needed for applications where power input is not a critical factor, however, power can be reduced by adding a conventional suction valve in parallel to the flow fitting 20. This is illustrated in FIG. 1 and designated by the numeral 30. The by-pass intake conduit is connected at one end to cylinder 10, and at the other end to intake conduit 19 up-stream of the flow fitting 20. The conventional intake 30 is equipped with an inlet check valve 31, Which may take the form of a resilient metal member supported in recesses 32 and 33 in the side walls of cylinder 10 and which closes the inlet port 34 whenever no suction is applied by piston 11.

An alternative form of the invention is seen in FIGS. 3 and 4, in which numerals are employed that correspond to the numerals employed in FIGS. 1 and 2 but which have been increased by 100. Thus, the numeral 110 designates a cylinder, 111 a piston, 112 a piston rod, and 113 the wristpin. An exhaust port is designated by the numeral 114, being closed by valve 116, while a conventional suction port is designated by the numeral 134, being closed by a valve 131. An intake conduit in this form of the invention is designated by the numeral 119 communicating with the evaporator by means that are not shown. A tubular port member 120 is slidably, sealingly mounted in intake conduit 119 and is adapted to be positioned by means of rod 120a.

The intake conduit 119 is provided as part of the cylinder wall, as can be best appreciated from FIG. 4. The intake conduit 119 communicates with the interior of cylinder 110 through an elongated slot 122, which is adapted to be closed by the port member 120. Port member 120 is notched as at 120b, so that even in the extreme down position as shown, it does not completely isolate conduit 119 from cylinder 110. In the uppermost position of port member 120, the conduit 119 and the cylinder are in continuous commun cation, so that the compressor is completely unloaded. It is to be appreciated that member can be positioned intermediate two adjoining cylinders, thus varying the capacity of each-or a plurality of such members can be employed, each operated from a common shaft, so that each cylinder is unloaded to the same degree. A form of the invention where one port member serves two adjoining cylinders can be seen in FIG. 5, where member 220 is slidably mounted in the intake conduit 219 common to both cylinders 210 and 210a. Port member 220 is positioned by rod 220a connected to an eccentric 22%. For individual port members for each cylinder, the shaft 226C to which the eccentric 22% is attached may be arranged parallel to the crankshaft 212 instead of transverse as shown. In this manner each of a number of positioning rods such as 220a can be simultaneously positioned.

In this illustration given in FIGS. 3 and 4, any intermediate degree of effective stroke of the piston 111 can be obtained by positioning the port member 120 by moving rod 120a. Alternatively, rod 120a may extend inward, i.e., through the bottom wall of conduit 119, which has been designated 119a, for control from within the crankcase of the compressor. It is also to be appreciated that a solenoid and spring structure can be employed with rod 120a to provide the operation described in connection with FIG. 1.

This invention provides a number of advantages over prior art structures employed for the same purposes. The invention here, when employed in conjunction with a compressor, does more than merely unload the compressor, as was the case with prior art devices. Here, it is possible to reduce the capacity of the compressor cylinder. In a multi-cylinder compressor, it is possible to reduce the capacity of all cylinders an equal amount. In contrast to this, many conventional unloading means for cylinders ermit only complete unloading, one by one. This results in unequal torque in some of the drive means. Such a conventional uuloader is described in my prior Patent No. 2,761,616, issued September 4, 1956. 'In contrast to this, the invention here permits a smooth reduction of capacity. Furthermore, in conventional systems, it is usual to unload all but 20-30% of the cylinders in a multi-cylinder compressor, as to unload all of them would result in cessation of flow of gas and therefore of cylinder cooling. By keeping at least one or two cylinders cool by continuing their flow, it was hoped that the rest would be cool, also. In the inventive device, at least a minimum fiow can be provided for each cylinder, irrespective of the number, thereby attaining cooling of each.

While, in the foregoing specification, a detailed description of the invention has been given for clearness of understanding, those skilled in the art will perceive many variations in those details without departing from the spirit and scope of the invention.

1 claim:

1. In a gas compressor,

A. a cylinder having interior top and side walls, said cylinder being equipped with an opening in said interior top wall, means containing a gas communicating with said opening,

B. a piston mounted in said cylinder for reciprocal movement defining intake and compression strokes,

C. a tubular element mounted in said opening for movement therein parallel to the piston movement and independent of the movement of said piston, said piston being equipped with a projection extending upwardly therefrom for sealing receipt in said tubular element, and means for positioning said element in said opening to provide gas flow therethrough during selected initial portions of the piston compression stroke up to and including substantially all of the piston compression stroke.

2. The structure of claim 1 in which said projection is located on the axis of said piston.

3. The structure of claim 1 in which means are associ ated with said tubular element for restricting upward movement of said element to necessarily engage said element and projection just prior to the completion of said compression stroke.

4. The structure of claim 1 in which said means is adapted to position said element to provide gas flow therethrough during all of said piston compression stroke.

5. In refrigeration apparatus,

A. a cylinder having top and side walls defining a compression chamber,

i. said cylinder being equipped with an opening in said top wall, ii. means containing refrigerant gas communicating with said opening, iii. port means in said cylinder for introducing and removing refrigerant gas,

B. a piston mounted in said cylinder chamber for reciprocal movement defining intake and compression strokes,

C. a tubular element mounted in said opening for movement therein parallel to the piston movement and independent of the movement of said piston,

i. said piston being equipped with a projection extending upwardly therefrom for sealing receipt in said tubular element,

ii. and means for positioning said element in said opening to provide gas flow therethrough during selected initial portions of the piston compression stroke up to and including substantially all of the piston compression stroke.

References Cited in the file of this patent UNITED STATES PATENTS 289,079 Fonts Nov. 27, 1883 591,584 Barbour et al. Oct. 12, 1887 1,036,934 Toaz Aug. 27, 1912 1,487,770 Tuttle Mar. 25, 1924 1,998,751 Creveling Apr. 23, 1935 2,213,743 Miner Sept. 3, 1940 2,338,486 Bixler Jan. 24, 19474 2,524,235 Schenk Oct. 3, 1950 FOREIGN PATENTS 60,660 Austria Aug. 11, 1913 

1. IN A GAS COMPRESSOR, A. A CYLINDER HAVING INTERIOR TOP AND SIDE WALLS, SAID CYLINDER BEING EQUIPPED WITH AN OPENING IN SAID INTERIOR TOP WALL, MEANS CONTAINING A GAS COMMUNICATING WITH SAID OPENING, B. A PISTON MOUNTED IN SAID CYLINDER FOR RECIPROCAL MOVEMENT DEFINING INTAKE AND COMPRESSION STROKES, C. A TUBULAR ELEMENT MOUNTED IN SAID OPENING FOR MOVEMENT THEREIN PARALLEL TO THE PISTON MOVEMENT AND INDEPENDENT OF THE MOVEMENT OF SAID PISTON, SAID PISTON BEING EQUIPPED WITH A PROJECTION EXTENDING UPWARDLY THEREFROM FOR SEALING RECEIPT IN SAID TUBULAR ELEMENT, AND MEANS FOR POSITIONING SAID ELEMENT IN SAID OPENING TO PROVIDE GAS FLOW THERETHROUGH DURING SELECTED INITIAL PORTIONS OF THE PISTON COMPRESSION STROKE UP TO AND INCLUDING SUBSTANTIALLY ALL OF THE PISTON COMPRESSION STROKE. 